The present invention relates to an improved oscillator package, and more particularly to an improved oscillator package which can be mounted on a circuit board by surface mounting technique (SMT).
Traditionally, oscillators are packaged by metallic housings, and thus cannot be mounted on circuit boards by SMT since the metallic housings might cause a short circuit. A small outline molding technique has been proposed to obviate the above-mentioned problem, so as to allow the oscillators to be mounted on the circuit boards by SMT, which is currently and widely adopted.
In the field of small outline molding technique, a current process packages an oscillator by a plastic housing, which is compatible with SMT. Nevertheless, in the oscillator, the crystal must be housed in a cylindrical metallic housing since the plastic housing is not hermetic. The available frequencies provided by oscillators packaged this way are restricted to a small range since standard disk-type so-called AT cut crystals are not suitable; and only strip-type crystals can be used. Moreover, the cost for high frequency parts is significantly raised since oscillation cannot be generated by overtone.
Another current process, a so-called Multi-Layer Cofire process, for SMT clock oscillators utilizes a chip carrier and a Kovar lid to package the oscillator, and the package is sealed by a gold-tin alloy thereafter. However, such a process is extremely expensive.
The present invention provides an improved oscillator package to mitigate and/or obviate the aforementioned problems.